At the time of this post, Delve boards are ridiculously annoying (nay impossible) to administer. They have no permissions on them, anyone in your tenant can create one, and they are all visible to all users. So what happens if someone creates an inappropriate one, or creates one with a misspelling? I created a test board to try Delve out and could not figure out how to delete it to save my life. I had to put in a support ticket.
My guess is that they’ll improve the administration end of this eventually, the boards will become a jumbled mess pretty quick if people start using them without any kind of management or permissions.
To remove a delve board, have everyone un-follow it – it’ll disappear. Can’t get people to un-follow it? Too bad… 😉